<div style="top:100px; left:100px; background-color:red">reeed</div>
<div style="top: 50px; left: 50px; background-color:rgba(0,0,255,0.5)">bluue</div>
<div style="top:125px; left: 25px; background-color:rgba(0,255,0,0.5)">green</div>
In Safari, this renders as: